The present invention relates to the art of closure devices, and, in particular, to devices which can provide a substantially air-tight seal without use of excessive amount of force.
It has been known in the art of package closure devices to provide simple independent closures which can be easily attached or installed manually or otherwise on flexible package openings with little or no effort required to control or respond to the packaging structure and peculiarities. For example, there are closure devices, such as security seals, which are applied to close bags, containers, or locks in such manner that the container or lock may only be opened by breaking the seal. These types of closures generally include a fastening head or body portion and an elongated flexible element attached thereto which has fastening elements that fit cooperatively with mating elements in the head portion. Examples of such closures are shown in U.S. Pat. Nos. 4,424,999; 4,306,745; 4,299,417; 4,263,697; 4,183,567; and 3,127,648. These devices do not provide any type of sealing characteristics. Thus, while they can be made relatively simply and are inexpensive, they are not useful for sealing packages having contents which require preservation from the environment.
In order to obtain sealed conditions, it has been known to provide a rigid opening whereby normal pressure sealing methods can be employed, e.g., welding, and application of sealing materials such as wax, etc. Known pressure sealing methods, however, require relatively expensive materials and equipment to effective proper sealing. Moreover, there is no presently known device for creating a sealing closure for a flexible package opening, which is easily applied and is disposable. Specifically in the case of a high pressure package, such as a vacuum pack or a superatmospheric pack, since the force required to establish the pressure package is high, it is usually necessary to employ a high degree of force in order to establish a sealed package.
Accordingly, it is an object of the present invention to provide a simple closure device for substantially hermetically sealing a pressure package.
It is another object of the invention to provide a closure device which can be easily locked in a sealing position with relatively little effort.
It is yet another object of the present invention to provide a closure device for substantially hermetically sealing a pressure package which can be made of inexpensive material.
Further objects of the present invention will be known to the practitioner by the description and drawings set forth herein.